7-[4-(4-Benzo[b]thiophen-4-yl-piperazin-1-yl)butoxy]-1H-quinolin-2-one (hereinafter also referred to as “Compound (I)”) is a benzothiophene compound represented by Formula (I):
Compound (I) or salts thereof are known to have serotonin uptake inhibitory activity (or serotonin re-uptake inhibitory activity) in addition to dopamine D2 receptor partial agonistic activity (D2 receptor partial agonistic activity), serotonin 5-HT2A receptor antagonistic activity (5-HT2A receptor antagonistic activity), and adrenaline α1 receptor antagonistic activity (α1 receptor antagonistic activity) (Patent Literature (PTL) 1). Compound (I) and salts thereof have a wide therapeutic spectrum for central nervous system diseases (particularly schizophrenia).